Storage of field crops, traditionally provided by structures such as silos and barns, can now be accomplished by large plastic storage bags. The bags, when filled with crop, extend typically up to twelve feet in diameter and up to 250 feet in length. A loading apparatus receives the field crop and controllably compacts the crop into the storage bag as the bag is deployed upon the ground behind the apparatus. The loading apparatus is equipped with an output feed rotor and the plastic storage bag is folded upon the loading apparatus with its open end exposed to the rotor to receive the crop material. The crop material is fed to the rotor and the rotor compacts the material in the bag as the bag is controllably deployed behind the loading apparatus. Thus, as the bag fills and unfolds from the loading apparatus, the apparatus moves away from the stationary portion of the bag lying on the ground.
A loading apparatus of this general type is described in U.S. Pat. No. 4,337,805 titled AGRICULTURAL BAG LOADING APPARATUS, issued Jul. 6, 1982 to Johnson et al., and assigned to the assignee of the present invention. The entire disclosure of U.S. Pat. No. 4,337,805 is incorporated herein by reference.
Forward propulsion for the loading apparatus results from the compacting force applied to the crop material within the bag. A stop positioned behind the bag and coupled to the loading apparatus by cables prevents rearward sliding of the bag. The cables wrap around drums on the loading apparatus and a brake mechanism of the drums resistively releases in response to pressure created as the rotor compresses the crop material. In other words, the loading apparatus is pushed forward by force feeding the crop material into the bag and against the stop. Thus, controlled crop compaction as well as forward propulsion is accomplished by resistively braking against forward movement resulting from loading of the storage bag.
The loading apparatus must be suitably positioned for each bagging operation. For example, to lay a storage bag along the edge of a field the loading apparatus must be first positioned along the field edge and pointed in a direction following the edge. If a second bag is to be laid down, the loading apparatus must be suitably repositioned within the field. Heretofore, such field repositioning between bagging operations has required manual wheel positioning, e.g., by crowbar, and coupling to a towing vehicle. Also, the loading apparatus must be movable between bagging sites, i.e., from field to field, typically along roadways. Such a loading apparatus typically cannot travel on roadways in its operational direction of travel due to its inordinate breadth. Accordingly, such a loading apparatus desirably travels also in a direction along its longitudinal axis, i.e., in a direction orthogonal to its operational direction of travel, for towing.
It has been suggested, in the above-noted U.S. Pat. No. 4,337,805, that the wheels of such a loading apparatus rotate through a steering angle of 90.degree. whereby the loading apparatus may be moved for transport as well as for field positioning use. As noted above, such wheel manipulation has been provided only by manual means such as by crowbar use and such field positioning has been provided by towing the loading apparatus.
Given the basic structure and operation of such a loading apparatus, it may be appreciated that operational steering control, field positioning between bagging operations, and transportation between bagging sites along roadways, can be difficult. Generally, the direction of operational travel, i.e., during a bagging operation, has been largely uncontrolled resulting in meandering storage bag placement. Selective braking for steering, i.e. braking one side more than the other, has been attempted, but such braking complicates the crop compaction process because braking is used to control crop compaction within the storage bag.
Accordingly, it is desirable that a crop loading apparatus be capable of properly collecting field crop by controlled crop compaction within the storage bag, and be capable of traveling conveniently in both an operational direction and in a transport direction with steering functions independent of braking functions in both traveling directions.